A physical model for the X-ray time lags of narrow-line Seyfert type 1 active galactic nuclei

ABSTRACT We present a large compilation of reddening estimates from broad-line Balmer decrements for active galactic nuclei (AGNs) with measured X-ray column densities. The median reddening is E(B − V) ≈ 0.77 ± 0.10 for type-1 to type-1.9 AGNs with reported column densities. This is notably higher than the median reddening of AGNs from the SDSS. We attribute this to the selection bias of the SDSS towards blue AGNs. For other AGNs, we find evidence of a publication bias against reporting low column densities. We find a significant correlation between NH and E(B − V) but with a large scatter of ±1 dex. On average, the X-ray columns are consistent with those predicted from E(B − V) for a solar neighbourhood dust-to-gas ratio. We argue that the large scatter of column densities and reddenings can be explained by X-ray column density variability. For AGNs with detectable broad-line regions (BLRs) that have undergone significant changes of Seyfert type (‘changing-look’ AGNs), we do not find any statistically significant differences in NH or E(B − V) compared to standard type-1 to type-1.9 AGNs. There is no evidence for any type-1 AGNs being Compton thick. We also analyse type-2 AGNs and find no significant correlation between NH and narrow-line region reddening. We find no evidence for a previously claimed anticorrelation. The median column density of LINERs is 22.68 ± 0.75 compared to a column density of 22.90 ± 0.28 for type-2 AGNs. We find the majority of low column density type-2 AGNs are LINERs, but NH is probably underestimated because of scattered light.

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Quasars as standard candles II

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935491 ◽

2019 ◽

Vol 631 ◽

pp. A120 ◽

Cited By ~ 7

Author(s):

F. Salvestrini ◽

G. Risaliti ◽

S. Bisogni ◽

E. Lusso ◽

C. Vignali

Keyword(s):

Active Galactic Nuclei ◽

Rest Frame ◽

Galactic Nuclei ◽

Observational Cosmology ◽

X Ray ◽

Uv Emission ◽

Wide Range ◽

Photon Index ◽

Lower Redshift

A tight non-linear relation between the X-ray and the optical-ultraviolet (UV) emission has been observed in active galactic nuclei (AGN) over a wide range of redshift and several orders of magnitude in luminosity, suggesting the existence of an ubiquitous physical mechanism regulating the energy transfer between the accretion disc and the X-ray emitting corona. Recently, our group developed a method to use this relation in observational cosmology, turning quasars into standardizable candles. This work mainly seeks to investigate the potential evolution of this correction at high redshifts. We thus studied the LX − LUV relation for a sample of quasars in the redshift range 4 < z < 7, adopting the selection criteria proposed in our previous work regarding their spectral properties. The resulting sample consists of 53 type 1 (unobscured) quasars, observed either with Chandra or XMM-Newton, for which we performed a full spectral analysis, determining the rest-frame 2 keV flux density, as well as more general X-ray properties such as the estimate of photon index, and the soft (0.5–2 keV) and hard (2–10 keV) unabsorbed luminosities. We find that the relation shows no evidence for evolution with redshift. The intrinsic dispersion of the LX–LUV for a sample free of systematics/contaminants is of the order of 0.22 dex, which is consistent with previous estimates from our group on quasars at lower redshift.

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The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stx795 ◽

2017 ◽

Vol 469 (1) ◽

pp. 110-126 ◽

Cited By ~ 1

Author(s):

I. García-Bernete ◽

C. Ramos Almeida ◽

H. Landt ◽

M. J. Ward ◽

M. Baloković ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

X Ray

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Discovery of a relation between black hole mass and soft X-ray time lags in active galactic nuclei

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stt339 ◽

2013 ◽

Vol 431 (3) ◽

pp. 2441-2452 ◽

Cited By ~ 137

Author(s):

B. De Marco ◽

G. Ponti ◽

M. Cappi ◽

M. Dadina ◽

P. Uttley ◽

...

Keyword(s):

Black Hole ◽

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Time Lags ◽

Black Hole Mass ◽

X Ray

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THE GLOBAL IMPLICATIONS OF THE HARD X-RAY EXCESS IN TYPE 1 ACTIVE GALACTIC NUCLEI

The Astrophysical Journal ◽

10.1088/0004-637x/762/2/80 ◽

2012 ◽

Vol 762 (2) ◽

pp. 80 ◽

Cited By ~ 30

Author(s):

M. M. Tatum ◽

T. J. Turner ◽

L. Miller ◽

J. N. Reeves

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

X Ray

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A public relativistic transfer function model for X-ray reverberation mapping of accreting black holes

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1720 ◽

2019 ◽

Vol 488 (1) ◽

pp. 324-347 ◽

Cited By ~ 14

Author(s):

Adam Ingram ◽

Guglielmo Mastroserio ◽

Thomas Dauser ◽

Pieter Hovenkamp ◽

Michiel van der Klis ◽

...

Keyword(s):

Black Holes ◽

Black Hole ◽

Active Galactic Nuclei ◽

Radial Profile ◽

Galactic Nuclei ◽

Seyfert Galaxy ◽

Geometric Constraints ◽

Time Lags ◽

X Ray ◽

X Ray Binaries

ABSTRACTWe present the publicly available model reltrans that calculates the light-crossing delays and energy shifts experienced by X-ray photons originally emitted close to the black hole when they reflect from the accretion disc and are scattered into our line of sight, accounting for all general relativistic effects. Our model is fast and flexible enough to be simultaneously fit to the observed energy-dependent cross-spectrum for a large range of Fourier frequencies, as well as to the time-averaged spectrum. This not only enables better geometric constraints than only modelling the relativistically broadened reflection features in the time-averaged spectrum, but additionally enables constraints on the mass of supermassive black holes in active galactic nuclei and stellar-mass black holes in X-ray binaries. We include a self-consistently calculated radial profile of the disc ionization parameter and properly account for the effect that the telescope response has on the predicted time lags. We find that a number of previous spectral analyses have measured artificially low source heights due to not accounting for the former effect and that timing analyses have been affected by the latter. In particular, the magnitude of the soft lags in active galactic nuclei may have been underestimated, and the magnitude of lags attributed to thermal reverberation in X-ray binaries may have been overestimated. We fit reltrans to the lag-energy spectrum of the Seyfert galaxy Mrk 335, resulting in a best-fitting black hole mass that is smaller than previous optical reverberation measurements (∼7 million compared with ∼14–26 million M⊙).

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Swift monitoring and Suzaku spectroscopy of the γ-ray detected narrow-line Seyfert 1 galaxy 1H 0323+342

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315007504 ◽

2014 ◽

Vol 10 (S312) ◽

pp. 66-67

Author(s):

S. Yao ◽

W. Yuan ◽

S. Komossa ◽

D. Grupe ◽

L. Fuhrmann ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Broad Band ◽

Galactic Nuclei ◽

Optical Monitoring ◽

Narrow Line ◽

Black Hole Mass ◽

X Ray ◽

Small Black Hole ◽

Special Subset ◽

Γ Ray

Abstract1H 0323+342 is one of the rare γ-ray detected narrow-line Seyfert 1 galaxies (NLS1s), a special subset of active galactic nuclei (AGN) owing to their hybrid behavior of both NLS1s and blazars. The rarity of such kind of sources makes their properties far from being understood. We analyze simultaneous X-ray and UV/optical monitoring observations of 1H 0323+342 performed by Swift over ~7 years. The UV/X-ray correlation and the broad band SED reveal that the X-ray band is dominated by the disk/corona emission during the observations. The large normalized excess variance of the X-ray variability detected with Suzaku suggests a relatively small black hole mass of the order of 107M⊙, consistent with the estimation based on the broad Hβ line in the optical band.

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